During puberty, there is a marked acceleration of growth with increasing body size, muscle mass and changes in body composition. There is a multitude of hormonal changes which occur during puberty including, but not limited to, increased sex steroids and increased growth hormone/IGF-1 secretion. Whether or not pubertal changes in growth and mass accretion are the result of sex steroids vs GH vs a combination of both remains unresolved. The specific hypothesis to be tested is: During puberty, protein accretion and increased growth is achieved through increased sex steroids and GH in unison. In adolescents with delayed puberty, DHT supplementation will not be associated with sparing of protein breakdown if GH concentrations are not enhanced. Therefore, the objective of this research proposal is to (1) investigate the actions of DHT on invivo protein, fat and glucose metabolism and (2) to assess its effects on GH, IGF-1 and IGF-binding protein levels in adolescents with delayed puberty.